Yes you can do that easily.
Just start with an empty project, add your instrument, and write.
Note that by default you will get more than one layout in the project. The full score is in concert pitch by default. The parts (one for each player in the score) are in transposed pitch. So if you want to write “as on paper”, use the part layout, not the score.
There are two things you need to know:
1 . When you add a key signature, you specify the concert pitch not the transposed pitch. (That makes sense in a bigger score, where the key signature applies to all instruments which may have different transpositions or no transposition at all).
2. If you input notes using a keyboard (either MIDI or computer), set the Write / Input pitch option in the menu to specify whether the note names are written pitch or sounding pitch.
You can flip any layout between transposing and non-transposing with the tick boxes in the Edit menu, but for your simple situation you don’t need to do that.
Note that “transposing instruments” and “transposition” are two different things. “transposition” is more complicated (especially if you are defining your own tonality systems!) but it’s irrelevant for your question.